Story of Psychology - Morton Hunt [349]
Quite reasonably, a third position has been taken for some time by many theorists: There are several types of representation—propositions, mental models, and images, each encoding information at a different level of abstraction. Finally, a fourth position is that different types of mental imagery use different brain networks: imagery involving spatial relations (as in imaginary rotation of an object) relies on a network in the parietal lobes, while imagery involving high-resolution shapes relies on a network in the occipital lobes.50 (Even if true, that position doesn’t help us understand how the masses of neuronal impulses arriving by either network get to be “seen” by us as mental images.)
Schemas: In 1932 the English psychologist Frederic Bartlett told subjects folk tales from non-Western sources and then asked them to recall the tales. They remembered the stories inaccurately, inadvertently filling in gaps, modifying events so as to provide reasons for what happened, and omitting details that made no sense to Western minds. Bartlett concluded that “remembering is not the re-excitation of innumerable fixed, lifeless, and fragmentary traces” but “an imaginative reconstruction, or construction” based on our own organized mass of experiences. He called that organized mass “schemata”; others prefer the anglicized version “schemas.”51
Bartlett’s idea has been revived and elaborated in recent years. Schemas—also known as “frames” and “scripts”—are now thought of as packages of integrated information on various topics, retained in memory, on which we rely to interpret the allusive and fragmentary information that ordinary conversation—and even most narrative writing—consists of. In 1978, David Rumelhart, then of the University of California in San Diego, reported on experiments in which he read stories, sentence by sentence, to his subjects to see how and when they formed a clear idea of what the stories were about. When, for instance, they heard this: “I was brought into a large white room, and my eyes began to blink because the bright light hurt them,” some 80 percent at once assumed they were hearing either a hospital or interrogation scene, and supplied a wealth of information to the few words they had heard. If the next sentence or two contradicted this supposition, they changed it and filled out the story anew from a different schema.52
Much other recent work on schemas and a related type of information package known as a “script” has firmly established that it is by drawing on our expectations and organized knowledge structures that we understand and interpret—or often misinterpret—what we hear, read, and experience. Memory, in sum, is not only an information register to be consulted as needed but a program that directs our thinking.53
Forgetting: Many studies have explored why we forget some things and not others, and what can be done to improve memory, particularly in the elderly, most of whom undergo some degree of nonpathological memory impairment. (Normal age-related memory problems can often be ameliorated by mnemonic and other training. There is also the possibility that not far down the road a pharmacological treatment, rebalancing altered neurotransmitter output, will be found.)54
Much interesting research has concerned not the total loss of particular memories but the forgetting of important details and their replacement by new material. Our legal system relies heavily on the assumption that if we remember an event at all, we remember it as it was. The courts and many psychotherapists also believe that forgotten material retrieved through hypnosis is a true record of what happened. But psychotherapists have also long had evidence that we alter memories to make them more acceptable to the ego, and for many years Elizabeth Loftus has been amassing experimental evidence